I am the owner of a 2007 Yukon XL with 34k on the 5.3L motor. At 26k it started to burn oil, 1 qt every 2-3K miles. Now its up to 2 qts with 1k since the last oil change. GM says its normal to go through 1 qrt every 1 thousand miles. I say BS. They are starting an oil consumption test that will document who much oil the motor is going through. 3 dealers, no leaks. Last dealer added dye to the motor oil. I have to drive 86 miles one way to my new dealer since my dealer lost his franchise. GM told me that i cant add oil if it is low and that i had to take it like that to the dealer so that they can verify the amount of oil in the engine. GM also said they would not be responsible should anything happen to the engine en route to the dealer. Is this normal? Has anyone heard of a new vehicle going through that much oil in a GMC? This is my first GM and maybe my last. We bought this new and are past the 3/36k warranty. Good thing we still have the 5 yr/100k power train warranty. No smoke, leaks, at all. Not at cold start up or anytime.
'07 5.3L will have AFM (Active Fuel Management) and it is a known fact that these are prone to high oil consumption. (not every 5.3 AFM does this but it is becoming more common all the time right about at 30,000 miles)
GM is 'looking into this issues, if you bring this to the attention of your dealer he will likely put you on an oil consumption monitoring list. Which means wait because GM does not know what to do about it, sometimes the dealers will replace all the lifters on warranty, sometimes they will deny that they know anything about the issue/problem.
Some people will tell you that if you turn the AFM off (GM will not do that, you need to get an aftermarket tune or a handheld tuner) then the oil consumption goes away, BUT..SO DOES YOUR POWERTRAIN WARRANTY...!!!
There is a UPDATE TSB 10-6-01-008A. Paraphrased on another site by a GM mechanic "GM states that there is a new design oil scraper that is to now be used, to shield the pistons from nearby AFM valve oil splash. To install this special part, the oil pan must be dropped and reinstalled."
The issue, is recently being attributed to oil buildup on the walls of the de-activated cylinders due to continual oil spraying as these cylinders cool slightly, and this build-up then eventually leads to oil passing by the rings into the combustion chamber. I think this has something to do with the temperature differential with the deactivated cylinders going into a cooling and heating cycle as the spark/fuel is deactivated and then reactivated all then this seems to be leading to consequential impacts on rings and lifters.
So the GM proposed band-aid fix to install some type of deflector shield to limit the continued direct spray of oil on to the base of the de-activated cylinder, so that the oil build-up will not occur.
